1-phenyl-2,3-dimethyl-4-alkyl-5-pyrazolones



Patented Aug. 28, 1934 t i r V UNITED STATES PATENT OFFICE l-PHENYL-Zfi-DIMIETHYLA-ALKYL-- PYRAZOLONES Hans Stenzl, Basel, Switzerland, assignor to Hoff-V mann-La Roche Inc., Nutley, N. J a corporation of New Jersey No Drawing. Application September 15, 1932, lserial No. 633,377. In Germany October 9,

2 Claims. v (01. 260-45) Of the alkyl homologues of 1-phenyl-2,3- the l-phenyl-Z, 3 dimethyl-4 isopropyl-pyrazodimethyl-5-pyrazolone the 1-tolyl-2,3-dimethyllone congeals, It is re-crystallized from petrolepyrazolone and the 1-phenyl-2-ethyl-3-methylum ether and obtained in colourless crystals meltpyrazolone are already known. Both these com-' ing at 103 C. 7 pounds are but very slightly superior in action to l-phenyl-2,3-dimethyl-5-pyrazolone. A further possibility of obtaining homologues lies in 475 parts of n-propyl-pyrazolone are well mixed alkylating the 4-position. Of the derivatives thus with 365 parts of dimethyl-sulphate and slowly obtainable an action superiorto that of the nonheated to 125 C. After three hours 1600 parts 10 methylated compound in 4-position is ascribed to of 3-11-solution of sodium hydroxide are added 05 the 4-methyl-compound, but evidently this action and the reaction product. boiled for 30 minutes is not particularly strong. None of these comlonger; The mixtureis then poured into water pounds has attained any practical value. It was while stirring, whereby the 1-phenyl-2,3 'ditherefore surprising to find that by the introducmethyl-4-npropylpyrazolone congeals. It is retion of alkyl radicals, consisting of a chain of 3 crystallized from a mixture of petroleum ether. 7 carbon atoms, into the 4-position compounds with a small quantity of ether while thoroughly may be obtained, which in action are far superior cooling and obtained in soft feathery crystals to 1 phenyl-2,3-dimethyl-4-dimethyl-amino-5 melting at 57 C. pyrazolone, their action being 6 to 8 times as Y Y strong as the action of 1-phenyl-2,3-dimethyl-5- I I Example 3 g I pyrazolone. They are well crystallized, in water 10 parts of l-phenyl-3-methyl-4-allyl-pyrazodiflicultly, in most organic solvents easily soluble lone are heated with a mixture of parts of compounds, which are obtained in the usual manmethyl-alcohol and 6 parts of methyl-bromide ner by methylating the corresponding 4-alkylfor 9 to 10 hours to 100 C. und Pressure. After 25 pyrazolones, evaporating the solvent a solution of sodium To this group, characterized by a side-chain ydroxide is added in excess and that part Of t comprising three carbon atoms, there also belong mixture, which is insoluble in alkali, removed with the derivatives with unsaturated side-chain. t After y g and evaporating the ether,

Kobert (Zeitschrift fiir Klinische Medizin, 62, th 1-pheny1- ,3-dim t y r -a 1 -py a l n r 30 1907, page 98) describes the action of a compound mains; it is re-crystallized from petroleum ether 8 he calls d-allyl-antipyrine, without giving any inand obtained in lour crystal m lting at dications of its preparation, melting point and It s luble to the extent of 3.9% in analysis. The compound is easily soluble in wawat r at n rmal p a u t s u y in ter, is used in slightly warmed solution, its soluwater is gr a y r duced by the addition of sodi- 3 bility is heightened by the addition of soda. The -Q e or by warming to 0dt l a- 90 product dyes a mixture of potassium-ferri-cyanture. A mixture of potassium-ferri-cyanide and. ide and ferric chloride blue, The 4-al1yl-comferric chloride is nOt dyed blue with the. 91001101 pound obtained according to Example 3 shows Solutiflnnone of these properties. Its constitution has Y catalytic yd a o the -P y1- been well defined by analysis and byits convertidimethyl-4allyl-pyrazolone is converted into the 95 bility into the 4-n-propyl-compound by catalytic -D 3- y -P D -Py Z hydrogenation. The compound described by Ko- 1 Claim} J I bert consequently was not -allyl-1-phenyl-2,3- 1. The 1phe y -d hy p py -py- Example 2 dimethyl-pyrazolone. razolone', crystallizing in colourless needles melt- The new compounds are to be used as mediat 0 the w Compounds being d i 1 ficultlysoluble in water and reacting neutrally on ExampleI litmus paper, easily soluble in dilute mineral m 475 parts of l-phenyl-3-methyl4-isoproDyl- :f i 0st orgamc Solvents Insoluble m I,

methyl-Sulphate and Slowly heated to where R represents an alkyl radical-containing After 3 hours 1600 parts of 3-n-solution of sodithree carbon t um hydroxide are added and the reaction product boiled for 30 minutes longer. .The mixture is HANS STENZL.

then poured into water while stirring, whereby 110 pyrazolone are well mixed with 305 parts of dih dimethyl 4 R pyrazolene V 

